Range-predicting apparatus



E. MEITNER.

RANGE PREDICTlNG APPARATUS.

Patented Aug. 16, 1921.

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RANGE PREDICTING APPARATUS.

APPLxcATsoN FILED MAY 4. 1915. 1,387,551 Patelled Allg. 16, 1921.

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E. MEITNER.

RANGE PREDICTING APPARATUS.

APPLICATION HLED MAY 4.1915.

Patented Aug. 16, 1921.

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E. MEITNEH.

RANGE PREDICTING APPARATUS.

APPLICATION FILED MAY4.1915. Y 1,387,55L Patented Aug. 16,1921.

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E. MEITNER.

RANGE PREDICTING APPARATUS.

ArPucATloN man MAY 4. 19|5. Patented Allg. 16, 1921.

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ATTORNEY E. MEITNER.

l RANGE PREDICTING APPARATUS. I APPLICATION FILED MAY 4. I9I5.

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E. MEITNEH.

RANGE PREDICTING APPARATUS.

APPLICATION FILED MAY 4, 1915.

Patented Aug. 16, 1921.

SHEES-SHEET 7.

i i l UNITED STATES PATENT OFFICE.

ELEMER MEITNER, OF BROOKLYN, NEW YORK. ASSIGNOR, BY MESNE ASSIGNMENTS,

TO FORD INSTRUMENT COMPANY, INCORPORATED. OF NEW YORK, N. Y., A COR- PORATION OF NEW YORK.

RANGE-PREDICTING APPARATUS.

Application led May 4, 1915.

To allzu/10m it may concern Be it known that I, Dr. ELEMER MEITNER, a subject of the King of Hungary, residing at Brooklyn, N. Y., U. S. A., have invented certain new and useful Improvements in Range-Predicting Apparatus, of which the following is a specification.

This invention relates to range predicting and indicating apparatus for automatically indicating the variations of range between a gun and its target, so that the gunners may have constantly before them the correct range.

The objects of this invention are to co'nstruct a new and improved complete system for mechanically ascertaining from the data that is readily obtainable on the average war ship the average rate of change of the range, and for automatically transmitting such range to an instrument which I terni the range clock, which compounds said rate of change with the initial range so as to show either or both the probable range at each progressive instant and the probable predicted range a predetermined interval ahead of the present time.

According to my invention. use is made Specification of Letters Patent.

Patented Auo. 16, 1921.

serial No. 25,695.

Fig. 4 is a sectional elevation of the tracing device.

Fig. 4a is a diagram of the circuits of the transmitter and motor of the range calculator.

Fig. 5 is a bottom view of the tracing device.

Fig. 6 is a sectional elevation of the mechanical calculator forming a part of the range estimator.

Fig. 6a is a diagram of the circuits of the calculator.

Fig. 7 is a wiring diagram of the entire system.

Fig. S is a plan View of a modified form of range clock.

Fig. 9 is a detail thereof.

Figs. l0 and ll are perspective views of a couple of details of portions of Fig. 6. Fig. 1Q is a detail of the tracing device shown in Fig. 4.

Fig. 13 is a fragmentary section taken on the line 13-13 of Fig. 3.

Fig. ll is a diagrammatic view showing the relation of the apparatus of Figs. 3 and 4 to other elements of the system.

In the preferred form of my invention,

of a novel recording or tracing instrument the auxiliary instruments which arc made for plotting the relative course of thc target use of to obtain the necessary data for my and for mechanically combiningT and transapparatus are the range finder 1 (Fig. T), mit-ting to a range clock the component of the target bearing telescope Q and the master said course in the direction of the gun. compass 3, although it will be apparent, as Preferably also I provide automatic means the description proceeds, that the latter inin the range clock for transmitting any one st-rument need not be used. or all of its readings to the gun turrets. Electrical transmitters 4, 5 and 6, on or Referring to the drawings: associated with the instruments, are cm- Figure l is a diagrammatic representation ployed to control at a distance repeater moof the internal mechanism of one ot' the intors T. S and 9, which form a partof the struments forming av part of my system. instrument which I term the rate of change which I term the'rangeclock w m*est'mafFUPtjQ)' Ths'n-st'ruiiet com- Fig. :2 is a plan view of another portion prises a tracing device l0 adapted to record of my apparatus which I term the rate of the relative course of the target on a sheet change estimator. A portion of this figure 11, in which the motors T, S and 9 are mounti-S in SGCOD- ed and a mechanical calculating device 12 Fig. 3 is a plan View on a larger scale of for obtaining from the chart indications the a portion o f said estimator. which I term approximate rate of change and for trans tracing device. mitting said rate automatically to the range clock 13 (Fig. 1). Vhile I employ separate names to designate these instruments, and

will necessarily have to describe them one by one, I wish it understood that they are 5 all used together to form my novel system, and that in its broad aspect, my invention is not limited to the exact details of these instruments.

The three motors 7, 8 and 9 above referred to, form a part of the tracing device lO (Figs. 3 and 4). The motor 8 is geared to the large gear 15, through pinion 16 and idler 17. Said gear 15 serves to drive one arm 18 of the diferent-ial or epicyclic train of gearing 19, the opposite arm of which is driven through large gear 20. For this purose gears 15 and 18 may be rigidly coupled. Said gear 20 derives its 1119-111911 from the compass motor 9, through pinion 21 and idler 22. The central arm 23 of the train, therefore, is controlled by the joint action of the compass and the target bearing telescope. Said arm 23 is pinned to the central shaft 24, adjacent the lower portion of which pinion 25 is mounted.

Meshing with said pinion is large gear 26 which is secured to the sleeve 27, rotatably mounted upon the central supporting stem 28. Said sleeve 2T carries a long radial arm 29, which is secured to said sleeve to revolve with the same.

Vhile I do not wish to be restricted to any specific gear ratios, it may be stated that the proportions should obey the following requirement. Assuming that the ship is stationary, the gearing should be such as to cause rotation of the arm 29 at the same angular velocity as the target bearing telescope; also assuming that the telescope is fixed with respect to the home ship, the gearing should be such as to cause rotation of the arm 29 at an angular velocity equal to the angular velocity of turning of the ship,

Assuming that the arm 29 is so placed on the chart as to correspond to the position of the target bearing telescope, this position will be automatically maintained. rl`hus` suppose that the target is stationary and that the home ship rotates through an angle A in a counter-clockwise direction. In order to keep ou the target the telescope must be rotated through an angle A in a clockwise direction. Now it will be noted that under this assumption the position of the telescope in azimuth is unchanged and it will be shown that the position of the arm 29 on the chart 11 is also unchanged. The repeater 9 (conder the above assumption tended to cause revolution of the arm 29 through an angle A in one direction while the repeater 8 (conchart was zero. It will thus be seen that the arm 29 maintains the same relative position on the tiXed chart 11 that the target bearing telescope maintains in azimuth. Motor 7 is geared to the large gear 30 through the pinion 31, mounted on the motor shaft. Said gear 30 as shown forms the central arm of an epicyclic train of gearing 32. The other driving arm of said train is rotated from the cent-ral arm 23 of the epicyclic train 19, through the gear 33 mounted thereon, idler 34 and gear 35.

The driven portion of train 32 comprises bevel gear 36, which serves to drive the pinion 37. Meshing with said pinion is a double faced gear 38, one face of which is formed with crown gearing 39. An idler 40 mayv b e used to transmit motion from said crown gear 39 to a pinion 41, secured upon a. long threaded shaft 42, which is mounted within the arm 29.

A slidable carriage 43 is mounted on thel arm 29, and is adapted to maintain itself at a distance from the center of the body portion 44 of the tracer which is proportional to the range of the target. For this purpose, the carriage is provided with a threaded portion 45, through wlbich the screw 42 is threaded, so that upon rotation of the screw through the range motor 7, the carriage 43 is moved accordingly. The tracer maybe provided with setting handles 46. the inner ends of which are provided with crown gears 4(3, which may be brought into mesh with one of the gears (2() or 30) of the epicyclical trains by pushing in on the handles. By this means the apparatus may be initially set so as to correspond to the readings of the master instruments. and may also be corrected if the motors fall out of step with their respective transmitters. Thus the handle 46 adjacent gear 30 will turn screw 42 through the instrumentalities already described and set the carriage 43 to its proper position on arm 29 with respect to the initial range, while the other handle adjacent gear 2() will set the angular position of arm 29 to show the initial target bearings.

Carriage 43 carries a tracing means 4T which is adapted to trace the relative course of the target with respect to the ship. Preferably also the carriage is provided with a time recording means 48 so that the relative speed of the target may be determined from the markings on the chart.

Each recording pen is independently supported err a stem 394 -previded-mlj acmiLitsL upper end with an enlargement 302 (Fig.

12.) A compression spring 303 surrounds 125 the upper portion of said stem and bears against said enlargement so as to hold normally each pen in an elevated position, and against the under surface of a rocker arm 49 pivotally moiuited within carriage 43. 130

.movement of said screw, however, it will be seen that the rocker arm above referred to will be rocked on its pivot and depress one or the other of the marking pens 47 or 48 so as to cause a mark to be recorded. This movement of screw 51 is accomplished automatically and periodically as follows: A double electro-magnet 55 is mounted on said tracing device. One coil 56 of said magnet is in circuit with a. button 57 upon the range finder or indicator, so that when said button is closed by the operator a circuit will be completed through the coil. The other portion 58 of said magnet is in circuitv with a clock 59, so that a current is sent through the magnet at periodic intervals.

Preferably means are provided to break the circuit through magnet 56 when the circuit through magnet 58 is completed. Such means (see F ig. 7) may comprise a relay 60, in the clock circuit, which automatically opens a switch 61 in circuit with the button 57 and magnet 56, when the contact 59 on the clock is closed.

The two magnets 56 and 58 are provided with a common armature 62, but are designed t-o pull the armature in opposite directions. Said armature is secured to a member 63, which is connected to screw 51, so as to move the same longitudinally. As shown, this connection comprises a slot 6st, in member 63, which loosely fits a portion of the pinion 52 on the screw 51. In the normal operation of the device, the pen 47 is held down while but-ton 57 is closed, but when the clock circuit is thrown in, the pen 47 is raised, and 48 lowered for an instant to make a dot 65. as will be readily apparent.

Referring now to Fig. 2 carriage 43, may be provided with supporting rollers 66 swiveled to arms 67 on the carriage to aid in supporting the long radial arm 29. Gradua- '---tions 68 Ymay-be provided on the-.arm--QQ-.so

as t-o indiate the range directly to the observer.

To make use of the indications on the chart, l prefer to provide the tracer with a pair of arms 69 swiveled on body portion 44, which serve to slidably support the protractor 70. It should be remembered that the data it is desired to obtain is the rate of change of the range.

lVhile the tracings on the chart furnish means by which this rate of change may be estimated, the following operation is necessary. Roughly speaking, the change in the range that takes place in a given interval is represented by the component of the relative course of the target during that interval in the direction of the target bearing line. To obtain this end we may resolve the line 71, representing the relative course or a given portion thereof, in the direction of line 72. This may be done either graphically or by multiplying the length of such portion of line 71 by the cosine of the angle 6. The latter method is preferred to obtain accurate results, and for this reason I provide the mechanical calculating device 12. which not only performs this multiplication and indicates the rate of change, but serves to automatically transmit this rate ot' change to the range clock.

This calculator comprises a cylinder 72, mounted on an axle 73, rotatably supported in brackets 74. Said cylinder is provided with a circumferential slot 75, which preferably follows the intersection of an inclined plane with the surface of the cylinder. As is well known. such a slot will impart motion to a slide which is free to move only in an axialdirection with respect to the cylinder, such that the movement of the slide is proportional to the cosine of the angle through which the cylinder is rotated. Accordingly, a circular scale 76 is provided on the axle of this cylinder so that this cylinder may be rotated through the angle 6 indicated on the chart. A linger piece 77 may be used to rotate the cylinder. A slide 78 is mounted in a slideway 79. which extends parallel to the axis of the cylinder. Said slide is provided with a pin or finger 8() adapted to work in slot 75. Said slide 78 is also provided with a pin 81, which is free to slide in a slot 82 of the long lever 83. pivoted at 84. so that the motion of the slide is transmitted to said lever.

The motion of the lever in turn is transmitted to; a slide 88 (see also Fig. 10) mounted on a longitudinal slideway 89, as hy means of grooves 96, which take over guides 10() on the slideway. A downwardly extending pin 97 may serve to connect the lever and s lide through slotl 82. The entire slideway 89 is mounted for transverse movement, being threaded at each end on screws 490 andAHfwhic-h awe rotated trom-.an-indi`H d l# cator 95. adapted to he set to correspond to the relative speed of the target as shown on the chart.. through any means such as bevel gears 92 and 93 and shaft 9i. A star wheel 395 may he provided to count the revolutions of indicator 95. A second slideway 85 is transversely mounted within the calculator 4 one portion of an electrical contact device adapted to control a reversible motor 352. As shown, said device comprises a brush or trolley 101 mounted on post 102 and a pair of contact pieces 113 and 11i-1, mounted on an extension 105 of slide 95. rlllie contactpieces are so connected to Ytllreveeppositely wound field coils 353 and 351 of motor 352 as to reverse it when the trolley crosses from one contact to the other. Current may be supplied to the contacts by sliding contacts or trolleys, represented at 301. 302 and 303.

Motor 352 not only serves to rotate screw shafts S6 and 87 through suitable geai'ing, such as idler 106 and gear 107, shaft 108 and bevel geai's 109 and 110, and thus to cause the slideway or carriage 85 to follow the movement of trolley 101, but also furnishes power for rotating a transmitter 151. which is adapted to transmit automatically the calculated rate of change of range to the range clock. By means of this follow-up s vstem. the multiplying linkage is relieved of the greater part of the strains incident to moving the slides and transmitter. 1f desired. indicating means may be provided on the calculator 12. whereby the iate of change may be shown thereon. Such means may assume the form of a stationary scale 111 and a pointer 112 mounted on carriage Coming now to the range clock proper, the rate of change is introduced through the repeater motor 150. which is in circuit with the transmitter 151 in the calculating device, 12. Since considerable power is required to actuate the mechanism within the range clock, and since the step-by-step type of repeater motor is likely to become unreliable it' overloaded, 1 prefer to introduce between tlie repeater motor and the driving parts a power multiplying device iii the nature of an electrical follow-up system. Said device is shown as comprising a reversible electric motor 152, with oppositely wound field coils Y153 and 151 for controlling the A reversing contact switch is provided, one portion of which is rotated by means Y of repeater motor 150. through suitable gears mounted on a rotatable arm 159, secured to thev shaft of gear 157, while portion 158 comprises a pair of reversible contacts 160 and 161 mounted on a disk secured to the shaft of motor 152. Mounted on the motoi shaft ai'e a pair of gears 162 and 162', the latter serving to drive a rate of change indicator 163 on the range clock through any form of suitable gearing 362. Gear 162 meshes with another gear 1621 mounted on a shaft 162c which carries at its opposite end a gear 16321 that meshes with gear 163, secured to shaft 257. Threaded on a portion of shaft 257, is a slidable carriage 166, on which is rotatably mounted a friction roller 167. A speed cone 16S, driven by a constant speed motor 169, is arranged to drive said roller- Motor 1.69-may be connected thereto. through bevel gears 170 and 171 and a fiexible or loose coupling 172, to permit a certain amount of freedom for the cone.

1 also drive from said motor one arm 173 of an epicyelic ti'aiii of gearing. through gears 171 and 175. The bevel gear 176 forming another ariii of said train is mounted on the squared shaft- 177. on which roller 167 is slid-ably but not rotatably mounted, so that rotation of the roller will rotate bevel gear 176. 1t will hence be seen that the driven bevel gear 177 of said train. will receive a motion which is the i'esultaiit of the motion of cone 16S and roller 167.

coil spring 173 may be provided to hold the cone into close engagement with the rollei'. Also means may be provided to accurately adjust the position of the cone with respect to the roller such as by threading the shaft 179 on which the cone is mounted in a fixed bracket 130 and by providing gearing 181 and 182 through which said shaft may be rotated from aA handle 183. Motion of the driven bevel gear 177 is transmitted by means of bevel gears 131 and shaft 18412L to bevel gears 135. and thence by means of shaft 186 to pinion 187. which meshesV with gear 18S.

Une arm of an epicvclic. train 190 is driven by said gear 133. the opposite arm being geared through gears 191 and 192 to a setting handle 193. Said setting handle is designed to be used both for initially setting the clock to indicate the initial range. and also to introduce the spotters correction. The amount of the spotters correction is shown on a dial 194.

Said dial is driven indirectly from gear 192. through another epicyclic train 195, in

Zero after each spotters correction is introduced. For this purpose. a setting handle 196 is provided. which drives the arni 197 of the epicyclic train 195.

The other driving arm 198 is rotated from gear 192. while driven arni 199 drives the dial 191 through any suitable form of gearing such as gear 200, idler 201, pinion 202 and bevel gears 203 and 204.

Returning now to the epicyclic train 188, the driven arm of such train is provided with gear 205, which drives gear 207 on the range indicator 208, which in this form of device is shown as a counter.

Means are provided whereby the indications of the range clock will be automatically transmitted to range indicators in the turrets, or in other convenient positions on the Ship. For this purpose, a transmitter 206 may be provided, which may be driven from gear 207, by pinion 208, through the shaft 209. Said transmitter is designed to govern a repeater motor 209, mounted to actuate some form of range indicator.

I also prefer to equip the range clock with means whereby a predicted range may be indicated. It will be seen that the indicator 208 will show at each instant the probable range at that instant, but it is often desired to know what the range will be a predetermined interval ahead of the present so that the guns may be trained for the future range and be fired when such predetermined interval elapses. For this purpose, the rotation of the indicator 208 is transmitted through shaft 209', pinion 210 and idler 211 to arm 212, of an epieyclic train 213.

The opposite arm 214 is driven from a computing mechanism, which will now be described in detail. The slide 166, which carries roller 16T, is also provided with a slot 215, extending at an angle to the line of movement of said slide. A slide 216 works in said slot, which is provided with a pivoted cross piece 217, adapted to slide in a slot 218, in a member 219. rIhe movement of member 219 is controlled by means of a crown gear 221, mounted on the shaft of a handle 220, said gear being adapted to mesh with a gear 222, upon the handle being pushed inwardly against the action of the spring 223.

Upon the shaft of gear 222 is mounted a bevel gear 223, driving gear 224, which carries gear 225. Gear 226, mounted on shaft 22T, meshes with gear 225, and serves to rotate rack pinion 228, which meshes with a rack 228 upon the under surface of member 219. The gear 222 also is used to rotate a dial 229. which serves to indicate the predicted time for which the apparatus is set. By combining the predicted time interval tion is the rate of change of range, the change of range for the predetermined interval may be determined. For this purpose, the slide 216 mentioned above is provided with a pin 230, working in a slot 2:31. in lever 232. Said lever is pivoted to the member at 233, and is slidably mounted in a sleeve 234, pivotally secured to a rod 235. Said rod is slidably mounted in xed bearings 236, and is provided With rack teeth 23T, whereby its motion may be transmitted to the indicator. For this purpose, a series of gears 238 may be provided, which drive through two bevel gears 241, shaft 240.

The motion of shaft 240 serves as a measure of the amount that mustbe added to the present range to show the future range. This amount may be added through the differential train 213 described above, the pinion 242 meshing with gear 214. The driven arm of said train rotates the predicted range indicator 245 through gears 243 and 244.

Also driven from said gear 243 is a pinion 246, which serves to drive transmitter 247, adapted to control repeater motors 248 in the turrets.

In connection with some of the setting handles on the range clock, I have shown an automatic lock which serves to lock that portion of the epicyclic train which is controlled through the setting handle, when the setting handles are not being used. These locks are shown as comprising a bell crank lever 250, one arm of which is normally pressed by means of a` spring 251 into engagement with the teeth of a gear or a notched wheel to lock the same. T he other arm is connected to a collar 252 on the setting handle so that as the setting handle is pushed in to engage the clutch teeth 253, the first mentioned arm of the bell crank lever is automatically lifted out of engagement with the teeth. thereby releasing the lock.

In connection with setting handles 183 and 220, coil springs 223 are made use of instead of fiat springs similar to spring 251. A setting handle 255 is also provided to adjust the position of the slide 166, said handle being adapted upon being pushed inward to engage clutch teeth 256, the driven portion of which are mounted on the shaft 25T of gear 163. In connection with this handle, a somewhat different form of stop is shown. Said stop comprises in this instance, an electro-magnet 25T in the circuit of motor 169, the armature 258 of said magnet serving as a lock for the toothed wheel 259 on shaft 25T as long as no current is passing through the motor circuit. But when motor 169 is running, the elect-romagnct will draw up armature 258 against the action of spring 260 and release the stop.

Thepurpose offthis arrangement is ttrmwe '#w -i l it impossible to adjust the roller 167 except when cone 168 is running, since an attempt to do otherwisel would injure the wearing surfaces of both the cone and roller.

Figs. 8 and 9 show a modified form of range clock in which the two range indicaters, present and predicted, are shown in the. form of two pointers 260 and 261, with a coperating dial 262 therefor. In order to give the dial a suiiicient range, it is gradis accomplished by varying the position of uated in the form of a spiral 263. friction roller 16T on the surface of speed One of they pointers 260, comprises a slidcone 168 according to the rate of change of able member 264, which is provided with range. Since this rate becomes both posia. pin 265, adapted to work in a spiral groove tive and negative, I introduce a differential 266, as the dial is rotated. By this means train 175 between roller 167 and the range a ready means of telling which portion of indicator, whereby the required result is the spiral should be used is provided, as the achieved without the necessity of stopping member 261 is automatically advanced by or reversing the roller. each complete rotation of the dial the radial The change of range is continually added distance between the successive convoluto the initial range through differential 190 tions. and the present range indicated at 208.

Pointer 261, which is preferably used for n The rate of change of range is also utithe predicted range, may be of simpler lized 1n the range predicting portion of the form, as, from the nature of the device, the clock, where it is multiplied by the predicted two pointers will always be read 0n the time by the linkage 21S-235, thereby indisame convolution. Dial 2.6%issshown as eating tl1.il111.01111t that IHUS .be added t0 mounted on a rotatable sleeve 26T, within the present range to obtain the Jfuture range. which a fixed hollow shaft 268 for pointer In Fig. l, thiS addition S performed by 26() is mounted. Pointer 261 may be monntdierential train 213, while in Figs. 8 and ed on a central shaft 269. The operating 9 it is performed by reading pointer 261 mechanism is not shown, since it may be on the movabledial 262. similar to the mechanism shown in F ig. 1.v lhile the two indicators 208 and 245 are except that shaft 269, carrying pointer QSL designed to be used as presentand future is rotated directly from the multiplying range indicators, other uses are possible, demechanism, as, for instance, from saaft 210 pending on the amplitude of the predicting (Fig. 1) without the interdisposition of a time. For instance, since indicator 208 does differential gearing 213. not show the precise present range. but

The operation of the entire apparatus is always lags a comparatively constant interas follows: The mechanical operation of the, val behind, due to the time taken to detracing device 10 needs no further explanatermine and transmit the range, indicator tion. it is thought. It should be noted, how- 245 may be set to indicate the true present ever, that the device would remain operative range, b v properly setting the predicting even if the compass motor 9 were omitted. time. Also use may be made of indicator as long as the ship kept on the saine course. 215 to allow for variations in the deflection and, since in practice the portions of the of the shell due to variable weather conditraced lines which are measured are short, tions` the otiicer in charge merely increasing that the device would give fairly accurate or diminishing slightly the indicated preresults without motor 9. dicting time to allow 'for increased or de- In using the device, the operator first alcreased deflection. lows a short line (71) to be traced. In In accordance with the provisions of the order to measure a port-ion of this line and patent statutes, I have herein described the the angle 0, he then may turn the arm 29 principle of operation of my invention, to-

out of the way as to the position shown gether with the apparatus which I now.con.

in Fig. 2, either by one of handles 16 or hv Sider to represent the best embodiment theregrasping the arm directly. The arms (if) of, but I desire to have it understood that and protractor are then moved into posithe apparatus shown is only illustrative and tion so that the angle 6 may be measured. that the invention can be carried ont by The length of a portion of line Tl such as other means. Also while it is designed to portion cl may be measured by a rule or use the various features and elements in the other instrument. IVhile the operator is combination and relations described, some of taking these readings, the tracer is recordthese may be altered and others omitted ing a new line 71', sothat a continuous without interfering with the more general record is obtained. results outlined. and the invention extends .The data obtained by the above mento such use.

tioned readings is placed in the calculator Having described my invention. what I mitter 151 transmits automatically the calculated rate of change of rangeto the range 1. The method of determining the rate clock 13. Said clock having been initiallyy of change of the range. which `consists in set to the range. as it was found to exist. mechanicallyvv recording as a single vector when the clock is started by handle 193. will the relative course and speed of Lthe target then automatically indicate the variable and resolving such a vector in the direction range, both at the present instant and at a of the instantaneousl target bearing as inpredetermined future interval. Briefly, this d icated on the chart as a single vector'.

Patent is:

2. The method of determining the rate ot change of range ot' a target which consists of plotting the relative positions of the target at successive time intervals and obtaining a single vector of the relative course and speed of the target and then resolving the vector thus obtained into its range rate component along the line of fire.

3. In a range indicator, the combination with means whereby the relative velocity and bearings of the target may be determined, of means for mechanically obtaining therefrom the rate of change of range comprising a cam slot adapted to be set to the angle between the relative course and the. target bearings, a slide adapted to be set to a position indicatingthe relative speed of the target, a pivoted lever having a pin engaging said cam slot and pivoted to said slide and aslide at an angle to said other slide connected with said lever, and means whereby the position of said last mentioned slide may be observed.

4. In a calculating device for combining a plurality of quantities, the combination with a plurality of indicators for the known quantities,v of an electrical contact controlled as a resultant of such quantities, a coperating contact therefor, a motor in circuit with said contacts, and connections between said motor and said coperating Contact whereby said contact follows the movements of said first mentioned contact.

In a calculating device for resolving a vector in a predetermined direction, a rotatably mounted cylinder having a slot cut on its surface which defines the points ot` intersection between an inclined plane and the cylinder, a slide engaging said slot and a guideway therefor, means whereby the c vlinder may be turned through the angle which the vector makes with respect to said direction. a slideway having a slide adapted to be set to indicate the vector, a second slidewav and slide at an angle to the first., a pivoted lever having a slidable connection with each of said slides and indicating means associated with said last mentioned slide.

(3. In variable range apparatus, consisting in the combination ot means for initially setting the apparatus to the present range. of a repeating device adapted to be actuated from a rate of change indicator, a continuously actuated member. means for compounding the movements of said setting means.l said member and saidlepeating ile-crY vice. whereby the variable range is automatically indicated.

7. In optical indicating apparatus, a differential gear train including three arms` an indicator proper. driven by one arm of said train, automatic means for driving a second arm, a normally operative lock for the third arm, a normally inoperative manual set-ting means adapted to drive on actuation said third arm, and means whereby said lock is rendered inoperative on actuating said setting means.

S. In a range clock, a variable speed mechanism comprising' a speed cone, means for driving said cone at a constant speed, a friction roller driven by said cone, the p0- sition of said roller being set according to the rate of change of range` a differential train of gearing including three arms, one arm of which is driven by said driving means, while another arm is driven by said roller, whereby the third arm will remain at rest when the roller is adjacent a predetermined position on the cone.

9. In a range indicator, means for determining the change of range that takes place over a predetermined interval comprising a member having a slot constrained to assume a position with respect to the magnitude of the rate of change of range, a second member having a slot adapted to move parallel to said first mentioned slot, means for setting said second member in accordance with the time interval desired and perpendicular to the other slot, a common slide for the slots. a lever pivoted to said second member and to said slide, a bar constrained to move parallel to said second mentioned slot and slidably secured to said lever, and means for registering the movements of said bar.

l0. In a range clock. a range indicator, a spotters correction indicator. hand means for initially setting the range indicator and for introducing the spotters correction into said range indicator. a second hand means. a differential gear train, each of said means being connected to an arm of said train, and connections between the third arm of said train and said correction indicator, whereby it may be brought back to zero.

1l. In a range clock, a range indicator, av spotters correction indicator. hand means for initially setting the range indicator, and for introducing the spotters correction into said indicator, a second hand means, a differential gear train. each of said means being` connected to an arm ot' said train, connections between the third arm of said train said correction indicator, whereby it may be brought back to zero, and a releasable lock for the arm of the train to which the hand means are connected.

l2. In a range clock. a range indicator, a spottersdmrrection indicatore,hand metmsn for initially setting the range indicator, and for introducing the spotters correction into said range indicator` a second hand means, automatic indicating mechanism, a differential gear train. said first hand means, s aid mechanism and said range indicator being connected to the three arms ot` said train respectively. and a second differential train, one arm of said first train, said second hand means and said spotters correction indicator beingr connected to the three arms of said train, respectively.

13. In a range clock, ayariable Speed mechanism comprising a constant speed rotating member, a friction roller actuated by said member and positioned with respect thereto in accordance with the rate ot change, a three arm differential one arm of [SEAL] the said Letters Patent should beread with this correction therein that the same may conform to the record of the case in the Patent Office. i

Signed and sealed this 15th day of November, A. D., 19721.

which is driven at constant speed While an- 10 In testimony whereof I have signed my 15 name to this specification this first day of BIay, 1915. P

DR. ELEBER IVIEITNER.

` It is hereby certified that in Letters Patent No. 1,387,551, granted August 16,

i 1921, upon the application of Elemer Meitner, of Brooklyn, New York, for an im` l provement in Range-Prei'ttng Apparatus,Z -an error appears 1n the printed specii ication requiring correction as follows'. Page 7, lines 88 to 90, claim 9, strike out l the Words means for setting said second member in accordance with the time interval desired7 and insert `the same to follow the word slot, line 91; and that KARL EEN-SING,

Acting Commissioner of Patents. 

